Add optional round-target billboard display

src/main/java/us/tss3/blockparty/arena/Arena.java

@@ -10,6 +10,7 @@ import org.bukkit.entity.Player;
 import org.bukkit.inventory.ItemStack;
 import org.bukkit.scheduler.BukkitTask;
 import us.tss3.blockparty.BlockPartyPlugin;
+import us.tss3.blockparty.billboard.BillboardManager;
 import us.tss3.blockparty.config.ArenaConfig;
 import us.tss3.blockparty.floor.FloorManager;
 import us.tss3.blockparty.logic.ArenaPhase;
@@ -35,6 +36,7 @@ public class Arena {
     private final BlockPartyPlugin plugin;
     private final ArenaConfig config;
     private final FloorManager floorManager;
+    private final BillboardManager billboardManager;
     private final ArenaStateMachine stateMachine = new ArenaStateMachine(ArenaPhase.DISABLED);
     private final Random random = new Random();
     private final TargetColorSelector selector = new TargetColorSelector(random::nextInt);
@@ -56,6 +58,7 @@ public class Arena {
         this.plugin = plugin;
         this.config = config;
         this.floorManager = new FloorManager(plugin, config);
+        this.billboardManager = new BillboardManager(plugin, config);
         if (config.isEnabled()) {
             stateMachine.transition(ArenaPhase.WAITING);
         }
@@ -109,6 +112,7 @@ public class Arena {
 
     public void disable() {
         cancelAllTasks();
+        billboardManager.despawn();
         // Force reset players out regardless of state
         List<UUID> all = new ArrayList<>();
         all.addAll(players);
@@ -318,6 +322,7 @@ public class Arena {
             p.getInventory().setItem(8, display.clone());
             plugin.getSoundUtil().play(p, plugin.getConfigManager().getSound("target-select"), 1f, 1f);
         }
+        billboardManager.show(currentTarget);
     }
 
     private void setupBossBar() {
@@ -493,6 +498,7 @@ public class Arena {
         floorManager.cancelActiveTask();
         cancelAllTasks();
         round = 0;
+        billboardManager.clear();
         stateMachine.transition(ArenaPhase.WAITING);
     }
 
@@ -516,6 +522,7 @@ public class Arena {
     /** Called on plugin disable / world unload to safely stop everything and restore players. */
     public void shutdown() {
         cancelAllTasks();
+        billboardManager.despawn();
         List<UUID> all = allParticipants();
         for (UUID uuid : all) {
             Player p = plugin.getServer().getPlayer(uuid);
@@ -529,6 +536,10 @@ public class Arena {
         spectators.clear();
     }
 
+    public BillboardManager getBillboardManager() {
+        return billboardManager;
+    }
+
     private String formatMaterial(Material material) {
         String name = material.name().replace("_CONCRETE", "").replace("_", " ").toLowerCase();
         return name.substring(0, 1).toUpperCase() + name.substring(1);